/* | |
* Licensed to the Apache Software Foundation (ASF) under one or more | |
* contributor license agreements. See the NOTICE file distributed with | |
* this work for additional information regarding copyright ownership. | |
* The ASF licenses this file to You under the Apache License, Version 2.0 | |
* (the "License"); you may not use this file except in compliance with | |
* the License. You may obtain a copy of the License at | |
* | |
* http://www.apache.org/licenses/LICENSE-2.0 | |
* | |
* Unless required by applicable law or agreed to in writing, software | |
* distributed under the License is distributed on an "AS IS" BASIS, | |
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
* See the License for the specific language governing permissions and | |
* limitations under the License. | |
*/ | |
package org.apache.commons.dbutils; | |
import java.sql.ResultSet; | |
import java.sql.SQLException; | |
import java.util.Iterator; | |
/** | |
* <p> | |
* Wraps a {@code ResultSet} in an {@code Iterator<Object[]>}. This is useful | |
* when you want to present a non-database application layer with domain | |
* neutral data. | |
* </p> | |
* | |
* <p> | |
* This implementation requires the {@code ResultSet.isLast()} method | |
* to be implemented. | |
* </p> | |
*/ | |
public class ResultSetIterator implements Iterator<Object[]> { | |
/** | |
* The wrapped {@code ResultSet}. | |
*/ | |
private final ResultSet rs; | |
/** | |
* The processor to use when converting a row into an Object[]. | |
*/ | |
private final RowProcessor convert; | |
/** | |
* Constructor for ResultSetIterator. | |
* @param rs Wrap this {@code ResultSet} in an {@code Iterator}. | |
*/ | |
public ResultSetIterator(final ResultSet rs) { | |
this(rs, new BasicRowProcessor()); | |
} | |
/** | |
* Constructor for ResultSetIterator. | |
* @param rs Wrap this {@code ResultSet} in an {@code Iterator}. | |
* @param convert The processor to use when converting a row into an | |
* {@code Object[]}. Defaults to a | |
* {@code BasicRowProcessor}. | |
*/ | |
public ResultSetIterator(final ResultSet rs, final RowProcessor convert) { | |
this.rs = rs; | |
this.convert = convert; | |
} | |
/** | |
* Returns true if there are more rows in the ResultSet. | |
* @return boolean {@code true} if there are more rows | |
* @throws RuntimeException if an SQLException occurs. | |
*/ | |
@Override | |
public boolean hasNext() { | |
try { | |
return !rs.isLast(); | |
} catch (final SQLException e) { | |
rethrow(e); | |
return false; | |
} | |
} | |
/** | |
* Returns the next row as an {@code Object[]}. | |
* @return An {@code Object[]} with the same number of elements as | |
* columns in the {@code ResultSet}. | |
* @see java.util.Iterator#next() | |
* @throws RuntimeException if an SQLException occurs. | |
*/ | |
@Override | |
public Object[] next() { | |
try { | |
rs.next(); | |
return this.convert.toArray(rs); | |
} catch (final SQLException e) { | |
rethrow(e); | |
return null; | |
} | |
} | |
/** | |
* Deletes the current row from the {@code ResultSet}. | |
* @see java.util.Iterator#remove() | |
* @throws RuntimeException if an SQLException occurs. | |
*/ | |
@Override | |
public void remove() { | |
try { | |
this.rs.deleteRow(); | |
} catch (final SQLException e) { | |
rethrow(e); | |
} | |
} | |
/** | |
* Rethrow the SQLException as a RuntimeException. This implementation | |
* creates a new RuntimeException with the SQLException's error message. | |
* @param e SQLException to rethrow | |
* @since 1.1 | |
*/ | |
protected void rethrow(final SQLException e) { | |
throw new RuntimeException(e.getMessage()); | |
} | |
/** | |
* Generates an {@code Iterable}, suitable for use in for-each loops. | |
* | |
* @param rs Wrap this {@code ResultSet} in an {@code Iterator}. | |
* @return an {@code Iterable}, suitable for use in for-each loops. | |
*/ | |
public static Iterable<Object[]> iterable(final ResultSet rs) { | |
return new Iterable<Object[]>() { | |
@Override | |
public Iterator<Object[]> iterator() { | |
return new ResultSetIterator(rs); | |
} | |
}; | |
} | |
} |